Critical Thermal Maximum of Juvenile Spotted Seatrout (Cynoscion nebulosus) Reared for Summer Stocking in Texas |
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| Authors: | Dusty L McDonald Paul D Cason Britt W Bumguardner Shane Bonnot |
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| Institution: | 1. Texas Parks and Wildlife Department, Perry R. Bass Marine Fisheries Research Station , Palacios , Texas , USA dusty.mcdonald@tpwd.texas.gov;3. Texas Parks and Wildlife Department, Perry R. Bass Marine Fisheries Research Station , Palacios , Texas , USA;4. Texas Parks and Wildlife Department, Sea Center Texas , Lake Jackson , Texas , USA |
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| Abstract: | The critical thermal maximum of juvenile spotted seatrout (SL range 18–33 mm) was determined using a temperature increase of +0.26°C per hour. The critical thermal maximum (water temperature that was lethal to 50% of the test fish LT50]) for trial 1 was LT50 = 38.8°C, LT50 = 39.4°C for trial 2, and LT50 = 38.9°C for trial 3. Critical thermal maximums differed significantly (P < 0.05) between trials 2 and 3, whereas trial 1 did not differ among trials. This difference correlated with body size, where fish in trial 2 were significantly larger (P < 0.05) (mean = 27.6 ± 2.0 mm in SL) (mean ± SE) than the fish of trials 1 (mean = 23.1 ± 0.5 mm in SL) and 3 (mean = 21.5 ± 0.7 mm in SL), suggesting positive size dependence in the critical thermal maximum. |
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| Keywords: | Heat tolerance size dependence temperature thermal stress |
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